<?php
session_start();
function connect() {
	$con = mysql_connect("localhost","root","");
	if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

mysql_select_db("unwdmi", $con);
}


function drawGraph($stn) {
	
	$sql = "SELECT AES_DECRYPT(cldc,'@#dwave\$r') AS cldc, time
			FROM measurement
			WHERE stn = ".$stn."
			ORDER BY date DESC,time DESC LIMIT 1";
	$result = mysql_query($sql);
	while($row = mysql_fetch_assoc($result)) {	
			$_SESSION['values'][$stn][$row['time']] = $row['cldc'];			
		}	
		if(count($_SESSION['values'][$stn]) > 7)
		{
			array_shift($_SESSION['values'][$stn]);
		}
		
		$values = $_SESSION['values'][$stn];
		$img_width=400;
 		$img_height=300; 
 		
 		$margins=25;
 		
 		$graph_width=$img_width - $margins * 2;
 		$graph_height=$img_height - $margins * 2; 
 		
 		$img=imagecreate($img_width,$img_height);
 		
 		$bar_width=20;
 		$total_bars=count($values);
		$gap= ($graph_width- $total_bars * $bar_width ) / ($total_bars +1); 
		
		$bar_color=imagecolorallocate($img,0,64,128);
 		$background_color=imagecolorallocate($img,240,240,255);
 		$border_color=imagecolorallocate($img,200,200,200);
 		$line_color=imagecolorallocate($img,220,220,220);
 		
 		imagefilledrectangle($img,1,1,$img_width-2,$img_height-2,$border_color);
 		imagefilledrectangle($img,$margins,$margins,$img_width-1-$margins,$img_height-1-$margins,$background_color);
		
		$max_value=150;
 		$ratio= $graph_height/$max_value;
 		
		$horizontal_lines=20;
 		$horizontal_gap=$graph_height/$horizontal_lines;
 		for($i=1;$i<=$horizontal_lines;$i++){
			$y=$img_height - $margins - $horizontal_gap * $i ;
			imageline($img,$margins,$y,$img_width-$margins,$y,$line_color);
			$v=intval($horizontal_gap * $i /$ratio);
			imagestring($img,0,5,$y-5,$v,$bar_color);
		}
		
		for($i=0;$i< $total_bars; $i++){
			list($key,$value)=each($values);
			$x1= $margins + $gap + $i * ($gap+$bar_width) ;
			$x2= $x1 + $bar_width;
			$y1=$margins +$graph_height- intval($value * $ratio) ;
			$y2=$img_height-$margins;
			imagefilledrectangle($img,$x1,$y1,$x2,$y2,$bar_color);
			imagestring($img,0,$x1+3,$y1-10,$value,$bar_color);
			imagestring($img,0,$x1+3,$img_height-15,$key,$bar_color);
		}

		header("Content-type:image/png");
 		imagepng($img);
 		
 			
	
		
}


?>